An FIR filter is described by the following difference equation: Vin] = 1 . x[n] - 3.x[n - 1] - 3. x[n - 2] + 1.x[n - 3] The frequency response He12 rfdof this filter is equal to: a. He/2mfd) = exp(-13tfd. (1cos(2 tfd) - 3cos(if d)) Ob. He129fd) = exp(-131f d) · (2 cos(31f d) – 6cos(nef a) OCH 129fd) = exp(-12 mfd) . (2cos(if d) – 6cos(3 TIf d)) Od. Hel2mfd) = exp(-jrfa) · (2 cos(2 tif d) – 6cos(1f d))
